The present invention is directed to systems and methods useful in testing for a presence of an anomalous substance in a biological specimen. More particularly, the invention is directed to a diagnostic testing system for detecting a presence of occult blood in a fecal sample, the system being suitable for at-home use by an untrained individual, as well as other areas where good results are needed and a laboratory is not readily available or timely.
Over 140,000 new persons per year in the United States are afflicted with cancer of the colon and rectum, the disease occurring equally in both men and women. Contrary to many other forms of cancer, early diagnosis and treatment of colorectal cancer and its precursor polyps does result in a cure rate of 80% to 90%. If, however, the disease is not detected until the later stages, the cure rate drops significantly. Thus, early detection of the disease is important to successful treatment of colorectal cancer. For this reason, it is recommended that all individuals over age 50 with no family history of the disease be screened annually for colorectal cancers. Individuals with family history of the disease or other known risk factors should be screened annually beginning no later than age 40.
Conventional screening procedures consist of testing for occult (hidden) blood in stool samples provided by a patient. Typically, the patient must collect two separate specimens on a test card on each of three consecutive days, and then deliver the test cards to a laboratory. At the laboratory, a physician or lab technician rehydrates the samples and then applies developer liquid to each specimen's test element, which has previously been impregnated with a suitable chromogenic reagent, such as guaiac. If blood is present in the specimen, the chromogenic reagent will cause the test element to change colors when the developer fluid is added, indicating that fecal occult blood or a similar reactant has been found.
One factor deterring individuals from undergoing their recommended annual screening is the natural revulsion which many, if not most, people feel toward handling and looking at fecal matter. This revulsion may be amplified by the lack of a suitable implement for obtaining a specimen and applying it to the test element. Most test kits simply provide a wooden coffee-stirrer type stick which is somewhat difficult to manipulate and often, because of its generally smooth exterior surface, does not pick up a large enough sample or retain the sample without risk of dropping some of the fecal matter. Another unpleasant factor is the inconvenience and, sometimes, embarrassment associated with transporting or mailing the fecal matter specimens to a testing laboratory in a paper envelope.
In order to eliminate or reduce the aforementioned problems, various attempts have been made to develop a convenient test kit which requires a minimum of handling of fecal specimens, and can be performed by an untrained individual in the privacy of his or her own home. Examples of such attempts are disclosed in U.S. Pat. Nos. 4,582,685 and 5,196,167 to Guadagno et al., and U.S. Pat. No. 5,840,584 to Waldenburg. None of these prior art test kits have successfully met all of the needs of in-home users, however, and none has been approved by the United States Food and Drug Administration for over-the-counter sale.
An especially advantageous test kit is disclosed in Clawson et al., U.S. Pat. No. 6,436,714, having common inventorship herewith. Another advantageous test kit is disclosed in U.S. patent application Ser. No. 10/139,473, filed on May 3, 2002, now U.S. Pat. No. 7,189,356, issued on Mar. 13, 2007, and having common inventorship herewith.
The disclosure of each of the patents, patent publications and other publications identified herein is incorporated herein in its entirety by this specific reference.
There is still a need for improved test kits that are easy to use, hygienic and are effective in detecting even faint traces of a substance, such as fecal occult blood, in a biological specimen.